ESPN's European rugby review: Player of the weekend, flop & more

Following a thrilling weekend of knockout European rugby we have a much clearer idea who will lift the Champions and Challenge Cups.

Dazzling displays were many, but who really caught the eye, who disappointed and what are the big talking points as we reach the semifinal stage?

Player of the weekend

Leinster back row Dan Leavy scored the decisive try as his side ended Saracens' run as European champions. David Fitzgerald/Sportsfile via Getty Images

Champions Cup (Martyn Thomas): Dan Leavy (Leinster). It is the position he made his own for Ireland during the Six Nations, but Leavy was making only his second start of the season in his province's No. 7 shirt on Sunday. He carried on where he left off in the green of his country. Leinster boss Leo Cullen described Leavy's performance as "outstanding" after the 30-19 victory, and it was his try -- following a smart interchange with James Ryan -- that broke the back of Saracens' challenge. There was so much more to applaud, though, about a display that included 13 tackles and 79 metres run with ball in hand.

Challenge Cup (James Harrington): Toby Flood (Newcastle). The baby-faced fly-half always looks slightly worried his mum is about to call him in for his tea, but he was allowed to stay up late on Friday to set-up three of Newcastle's four tries as the Falcons clawed their way past Brive. It was his break and floated pass to Alex Tait that finally broke the French strugglers' will on the hour, when the game was still very firmly in the balance. A second perfect pass minutes later set Tait free for his second. A nod, too, for Djibril Camara, who shone in a losing cause for Stade Francais.

Flop of the weekend

Edinburgh were unable to convert their domestic form into a victory against Cardiff. Ian Rutherford/PA Images via Getty Images

Champions Cup: Francois Trinh-Duc. It may seem harsh, given the France No. 10 stepped off the bench and did more than most to put Toulon in a winning position against Munster at Thomond Park on Saturday. However, on a weekend of fine margins it was his inability to find touch six minutes before the end that handed home wing Andrew Conway the chance to be the matchwinner. Conway stretched high to keep Trinh-Duc's clearance in play, before a slack Toulon chase ensured a path opened up for the Ireland wing to score the decisive try and earn his side a 20-19 victory in Limerick.

Challenge Cup: Edinburgh. It could have been Brive -- but their perilous Top 14 position offers an excuse, as they have more pressing concerns ... and they, at least, put up a fight at Newcastle. Everyone, however, expected much more from Richard Cockerill's side, who rode into Murrayfield on Saturday on the wave of a seven-match unbeaten run -- only to put on a witless, hapless, brainless display against Blues. Frankly, they deserved to lose.

Champions Cup: Wayne Pivac. Having named a six-two forwards-backs split on his bench for the Scarlets' quarterfinal against La Rochelle, the last thing Pivac would have wanted to see was one of his wingers going down hurt inside the first 15 minutes. The Kiwi raised eyebrows as he decided to bring on Josh McLeod for Paul Asquith and switch flanker James Davies to the wing, but it proved a master stroke. Davies posses pace to burn and the skill set of a back, which was displayed neatly as he provided a deft touch to set Scott Williams free for the Scarlet's third try in their 29-17 win.

Challenge Cup: Johan Ackermann's decision to start Owen Williams at fly-half for Gloucester's trip to Connacht ahead of the Billys -- Burns and Twelvetrees -- prompted serious debate among pundits and fans. Williams, 26, had been a bench warmer since the Challenge Cup pool match against Pau in January. But he has cool-headed form when it comes to big matches -- and he did it again in Galway. He was calm and assured in a high-pressure encounter, and looked more at home with conditions than the hosts' Jack Carty.

Biggest refereeing call

All Blacks great Dan Carter came off the bench to inspire Racing against Clermont, but his pass for Marc Andreu was forward. THIERRY ZOCCOLAN/AFP/Getty Images

Champions Cup: Wayne Barnes (Clermont vs. Racing). There were plenty of contenders in Europe this week, and while you could write a book about the referrals Nigel Owens made during Munster's win over Toulon, the single biggest decision was made by Barnes and his team at the Stade Marcel Michelin. Dan Carter came on with a quarter of the game remaining, and within five minutes had created the game's deciding try -- finished off by man of the match Marc Andreu. But it should not have stood. Carter's pass to Andreu was clearly forward, and given the legendary All Black passed a metre before the 22 and the ball was collected on it, it should not have been difficult for TMO Rowan Kitt to spot. Barnes deserves praise, though, for officiating as much as he could in French.

Challenge Cup: JP Doyle (Pau vs. Stade Francais). The Champions Cup had a near-monopoly on quarterfinal refereeing controversies, leaving the way clear for some deserved praise for Doyle, the man with the whistle at Pau's Stade de Hameau for their last-eight match against defending champions Stade Francais. Doyle kept control of a thrilling, eight-try game with quiet aplomb -- and did the whole thing in perfectly decent French, only resorting to English when absolutely necessary. Chapeau, Monsieur.

Champions Cup: The vagaries of the selection process for 'neutral' semifinal venues in the Champions Cup were laid bare this weekend. While Racing 92 will make the near-600km journey from south Paris to Bordeaux for their last four encounter with Munster, Leinster's victory over Saracens means they will remain at the Aviva Stadium to play Scarlets. No other side with a shot at home country advantage was scheduled to stay in their own city had they won, let alone play in a stadium that they use regularly. International venues are at a premium in Ireland, but that fact should not provide Leinster with an inherent advantage.

Challenge Cup: Although they lost at Pau, Stade Francais did not play like a side with relegation on their mind. But that's the reality of their Top 14 situation. With four games left -- including home matches against Clermont and fellow strugglers Brive, and away days at Lyon and La Rochelle -- Stade are three points from an instant drop to the ProD2 and two from a survival playoff. If the Jekyll-and-Hyde Parisians can finish their season like they played at Pau on Friday, survival is a near certainty. If, however, they play like they did against the same opponents in a Top 14 meeting back in February, they're in serious danger.